I built a 4 m deep, 5 m long structure 20 years ago; dug two trenches along for two rows of foundations, 3 foundations in each trench. The foundations were cast in 200 mm drainage pipes with reinforcement bars and post shoes on top. The pipes were placed on concrete slabs in the trench. A drainage pipe was laid in each trench and after backfilling against the foundations, ground insulation was placed 15 - 20 cm below the ground surface. Load-bearing beams 195x45 were placed in the post shoes.
